Abnormal Central Venous Oxygen Saturation As a Predictor of Mortality in Patients with Sepsis and Polytrauma in the Surgical Intensive Care Unit

Original Article ISSN (O): 2456-7388; ISSN (P): 2617-5479

Abnormal Central Venous Oxygen Saturation as a Predictor of Mortality in Patients with Sepsis and Polytrauma in the Surgical Intensive Care Unit

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T Vijaya Kumar , Srinivas , A. V. Mahesh 1MD, Department of Anesthesiology, Lalitha super speciality Hospital, Guntur, Andhra Pradesh, India, 2Consultant Physician and Intensivist, Lalitha super Specialty Hospital, Guntur, Andhra Pradesh, India, 3DNB, Department of Anesthesiology, Lalitha Super Speciality Hospital, Guntur, Andhra Pradesh, India.

Abstract

Background: In postoperative heart surgery patients and patients with sepsis, pathological (low and supranormal) central venous oxygen saturation (ScvO2) was shown to be associated with lower mortality. The objective is we want to examine the effect of sepsis and polytrauma infection on our surgical ICU and the incidence of morbidity and death in the population. Subjects and Methods: In such patients who met the qualifying criteria and had a history of scepticism and multi-trauma, a retrospective observational review was conducted. We investigated and evaluated the association between SCV02 and mortality and other variables, such as lactate and baseline excess and period of the ICU stay and inotropic assistance within the first 6 hours, using a multivariate model review. Their entry was measured and 6 hours later. Result: The incidence of deaths in the hyperoxia group was 2.4 times higher in comparison to the general population, and the death rate in the hypoxia category was 1.025 times higher. The risk of death for the hyperoxic population was 2.4 times higher. There was no statistically relevant discrepancy of ICU, inotropic treatment, coagulopathy, dialysis, apache-11 score, baseline excess and lactate between the three levels of Scv02. Conclusion: The base excess and Scv02 were not significant when the lactates were calculated to a mortality point, but the j curve revealed that both the hypoxia group and the hyperoxia mortality had improved in contrast with the normal oxy group. Since the small sample size was sufficient to predict a trend, secondary targets were not appropriate.

Keywords: Central Venous Oxygen Saturation, SCVO2, Normaloxia, Sepsis, Trauma, Lactate.

Corresponding Author: Srinivas, Consultant Physician and Intensivist, Lalitha super Specialty Hospital, Guntur, Andhra Pradesh, India. E-mail: [email protected]

Received: 30 July 2020 Revised: 02 September 2020 Accepted: 12 September 2020 Published: 16 December 2020

Introduction and oxygen usage in its critical form. Sepsis and trauma, the oxygenation of the heart’s blood, oxygen flow to tissue In ICU cases, sepsis and trauma are the primary causes of and oxygen consumption of the various tissues are separate death and illness. Typical properties of the two conditions pathways involved. are systemic inflammation and deformed oxygen supply. Unfortunately, multiple treatments on septic medications have This disparity can be easily observed and monitored, minimis- only recently improved their longevity. The three key goals of ing loss and reducing ICU patients’ morbidity and mortality [1] resuscitation are pre-loads, perfusion and tissue hypoxia. by administering oxygen and utilizing it. The Early Goal-Directed Therapy (EGDT) reported improved A low scvO2 therefore can result in the reduced systemic results in the first 6 hours after admission in hospital in supply of oxygen, an increase in oxygen production or both. septic patients with tailored haemodynamical parameters. The The EGDT protocol addresses poor ScvO2 by optimising treatment demonstrated that the oxygen supply was maximised oxygen supply by increasing the oxygen saturations, cardiac by improved central venous oxygen saturation and increased efficiency or the capacity to oxygen transfer. blood pressure results. As a consequence, the exchange of oxygen failures can Central venous oxygen saturation occurs by measuring the precisely be categorised into three losses: 1) macro-circulatory oxygen flow of the venous blood to the heart. It represents loss, 2) micro-circulating failure, and 3). Macro-circulatory a measure of oxygen use, the relation of oxygen availability dysfunction typically is measured by measures such as CVP, 99 99 Academia Anesthesiologica International Volume 5 Issue 2 99 July-December 2020 53 Kumar & Mahesh; Predictor of Mortality in Patients with Sepsis and Polytrauma

[2] mean arterial pressure (MAP) and cardiac output. Table 1: Baseline Characteristics data regarding gender and No matter whether the individual’s ScvO2 levels are minimal mortality or supranormal. Strong ScvO2 is a poorly understood alarm SCVO2 indicator for oxygenation of damaged tissue in patients with Hypoxia Normoxia Hyperoxia sepsis. In cardiac surgery patients it has been observed that (< 60) (60 to (75.1 to Supra-normal ScvO2 levels have traditionally been considered 75) 100) [3,4] with no therapeutic benefits. Gender Males 8 28 23 Females 3 10 8 Subjects and Methods Mortality Yes 1 2 5 Place of Study: Lalitha Super Speciality Hospital Intensive No 11 35 27 Care Unit (ICU). Guntur. Sample Size: 80 patients with a diagnosis of sepsis or Table 2: Correlation of ScvO2 to mortality at the time of polytrauma or both. admission and after 6 hours SCVO2 No. of No. of Inclusion Criteria: patients patients Patients with a diagnosis of sepsis and polytrauma have been Alive Dead admitted to ICU in the age range of 18 to 80 years. At the time of Low 9 - Exclusion Criteria: admission Normal 34 1 • Patients with Age <18 years or > 80 years, High 24 4 • Chronic lung disease 6 Hours Low 14 - • Pregnant women Normal 34 1 • Cardiac disease (moderate to severe left ventricular High 24 4 failure, Intra and extracardiac shunts. • Liver failure (acute or chronic) • Central venous catheter patients that do not have the tip hyperoxy population, death about normoxia was 2.4 times in the Superior vena cava. higher, but not statistically significant. In the hyperoxia population, the risk for mortality was 2.4 times higher, but in A blood sample from the central venous catheter, the tip comparison with the hyperoxia p-value was not significant. of which is situated in the upper vena cava, was obtained to ensure that the systemic oxygen saturation of the pulse oximeter is greater than 93 per cent as per the unit procedure. Table 3: Correlation of oxygen extraction ratio to ScvO2 At the same moment, an arterial blood sample was collected Oxygen SCVO2 for examination. For the study six hours after ICU entry, a Extraction Low Normal High comparable collection of central venous and arterial samples Low 4 34 17 were taken. A severe score of disease (APACHE II) has been registered 24 hours after hospital admission. Standard Normal - - 14 treatment was provided to patients. In the datasheet, the High 7 4 - need for inotropic medicine, ventilation and renal substitution therapy and their duration is documented during the treatment The oxygen extraction ratio was marginally lower in compar- cycle. ison to that of the hyperoxy group. The correlation of SCVO2 with ICU stay, dialysis, duration Results of inotropic treatment and coagulopathy involvement showed that both hypoxia and the population of hyperoxia needed a There were a total of 80 patients who satisfied the requirements slightly longer term of inotropic, additional need for dialysis for ICU admission. Thirty-three per cent were women and and coagulopathy. sixty-seven per cent were men. 88 per cent were reported for Septic Diagnosis and 12 per cent were confirmed for There was no statistically meaningful association between the Polytrauma. three SCV02 classes as compared to the APACHE II ranking, base excess, lactate point. It indicates that statistically, it is not important for the hyperoxia community to have higher mortality. In the 99 99 Academia Anesthesiologica International Volume 5 Issue 2 99 July-December 2020 54 Kumar & Mahesh; Predictor of Mortality in Patients with Sepsis and Polytrauma

Table 4: Incidence of coagulopathy with ScvO2 may be likely. In the case of adequate substrate distribution, SCOV2 Coagulopathy No Coagulopa- the blood flow could be maldistributed at the microvascular thy level or could be associated with a mitochondrial breakdown. Low 1 2 EGDT is focused on improved systemic availability of Normal 5 41 oxygen or macrocirculations by raising intravenous preload, raising oxygen delivery capability with red cells, increasing High 9 22 inotropic oxygen flow and an improvement in the pressure of vasoconstrictive perfusion. Microcirculation failure and Table 5: ScvO2 and need for dialysis mitochondrial failure can result in dysoxia, even if the [5] SCOV2 Dialysis No Dialysis macrocirculatory failure is fixed. Low 1 10 In a study by Mikkelsen, [6] initial elevated serum lactate Normal 2 36 patients in severe sepsis were associated with death irrespec- tive of the clinically obvious shock. While not statistically High 4 27 meaningful, our findings imply greater mortality in the higher level of lactate (> 2 mmols). The findings further show that in Table 6: cvO2 and lactates patients with hyperoxia, the inotropes are slightly longer and SCOV2 High Lactates Low Lactates the need for coagulopathic dialysis is higher. Low 7 1 While the meantime of ICU in the hyperoxia population was Normal 19 17 shorter, this was presumably attributed to the early mortality High 15 13 of these patients. Even in the population with hyperoxia, the oxygen consumption ratio was a lower yet higher mortality. It reinforces the concept of cell hypoxia after a major increase Table 7: Correlation of lactate levels to mortality in macrocirculatory collapse, leading to microcirculatory and Alive Death mitochondrial failure. In 27 critically ill septic patients, who Normal Lac- 33 1 had skeletal muscle biopsies within 24 hours of ICU intake, tate the therapeutic value of mitochondrial dysfunction in septic High Lactate 39 7 shock was seen. In 11 patients who died of sepsis, skeletal muscle ATP con- centrations were significantly lower than in 15 survivors, the Discussion marker for mitochondrial oxidative phosphorylation (MOPS). Thus, the cytopathic (or histotoxic) anoxia which cannot use A Pope et al. multi-centre study of patients with sepsis the oxygen given may explain cell injury and death from sep- was shown to be consistent with decreased mortality in sis. The most important cause of sepsis could be microcircula- both the hypoxia and the hyperoxia levels of the average tion (i.e. capillary). A reduction in the number of working cap- SCVO2. A multi-faceted assessment of the same group illaries due to shunts coincides with sepsis. The microthrombi indicated that hyperoxia was correlated with decreased often associate with a loss of blood supply. [7] mortality. There have been a few types of research to confirm Sepsis induces phenotypic variations in endothelial cells. this connexion. [1] Multivariate study found a high risk of Overt and indirect connexions exist between endothelial cells mortality in patients with hyperoxia (SCVO2 > 75 percent) on and components of the bacterial wall. Hyperlactemia in these admission, and in patients with normoxia and hypoxia 6 hours cases means that the microcirculation blood, even after resus- after admission, within a large population of SICU-patients. citation and macrocirculation normalisation, is being not dis- These guidelines show that venous hyperoxia (or insufficient tributed properly. Hypoperfusion is a consequence of micro- use of oxygen) can be of potential significance in the case of circulation. Such shutting down of inadequate microcircula- sepsis and polytrauma. tion networks in the organ beds promotes blood loss, thus While low SCVO2 may be a marker for macrocirculatory fail- reducing oxygen supply from the arterial to the venous field ure, high SCVO2 may be a microcirculatory or mitochondrial by hypoxic microcirculation. failure. In both cases, further studies on the cause of decreased Even with a sufficient macrocirculatory flow, microcirculatory oxygen consumption and alternative solutions must be carried failure can prevent the oxygen required and available from out. reaching the cells in vital organs. [8–10] A further revitalization Also, with adequate blood pressure and ample cardiac output, technique is then required to evaluate microcirculation damage also referred to as the enigmatic shock, Tissue hypoperfusion and use microcirculation-enhancing therapy. You should 99 99 Academia Anesthesiologica International Volume 5 Issue 2 99 July-December 2020 55 Kumar & Mahesh; Predictor of Mortality in Patients with Sepsis and Polytrauma consider some causes of mitochondrial dysfunction and s13054-015-0889-6. treatment methods to address those defects. During adequate 5. Tyagi A, Sethi AK, Girotra G, Mohta M. The Microcirculation global oxygen supply, we have found that high SCVO2 was in Sepsis. Indian J Anaesth. 2009;53(3):281–293. linked to increased death and that these observations are a 6. Mikkelsen ME, Miltiades AN, Gaieski DF, Goyal M, Fuchs target for further studies. BD, Shah CV, et al. Serum lactate is associated with mortality in severe sepsis independent of organ failure and shock*. Crit Care Med. 2009;37(5):1670–1677. Available from: https://dx. Conclusion doi.org/10.1097/ccm.0b013e31819fcf68. 7. ;. Available from: http://www.thelancet.com/journals/lancet/ The base excess and Scv02 were not significant when lactates article/PIIS0140-6736(02)09459-X/fulltext?refuid=S0196- were calculated to the point of mortality, but a curve in j form 0644. was showing greater mortality both in hypoxia groups and in 8. ; 2006. Available from: http://www.ncbi.nlm.nih.gov/pubmed/ hyperoxia relative to normalmoxia in the groups. Since the 16682924. small sample size was sufficient to predict a trend, secondary 9. Filippo AD, Gonnelli C, Perretta L, Zagli G, Spina R, Chiostri targets were not met. M, et al. Low central venous saturation predicts poor outcome in patients with brain injury after major trauma: a prospective observational study. Scand J Trauma Resusc Emerg Med. References 2009;17(1):23–23. Available from: https://dx.doi.org/10.1186/ 1757-7241-17-23. 1. Pope JV, Jones AE, Gaieski DF, Arnold RC, Trzeciak S, 10. Bakker J, Schieveld SJM, Brinkert W. Serum lactate level as a Shapiro NI. Multicenter Study of Central Venous Oxygen indicator of tissue hypoxia in severely ill patients. Ned Tijdschr Saturation (ScvO2) as a Predictor of Mortality in Patients With Geneeskd. 2000;144(16):737–741. Sepsis. Ann Emerg Med. 2010;55(1):40–46.e1. Available from: https://doi.org/10.1016/j.annemergmed.2009.08.014. Copyright: © the author(s), 2020. It is an open-access article 2. Perz S, Uhlig T, Kohl M, Bredle DL, Reinhart K, Bauer distributed under the terms of the Creative Commons Attribution M, et al. Low and “supranormal” central venous oxygen License (CC BY 4.0), which permits authors to retain ownership saturation and markers of tissue hypoxia in cardiac surgery of the copyright for their content, and allow anyone to download, patients: a prospective observational study. Intensive Care Med reuse, reprint, modify, distribute and/or copy the content as long . 2011;37(1):52–59. Available from: https://doi.org/10.1007/ as the original authors and source are cited. s00134-010-1980-8. 3. Nebout S, Pirracchio R. Should We Monitor ScVO2 in How to cite this article: Kumar TV, S, Mahesh AV. Abnormal Critically Ill Patients? Cardiol Res Pract. 2012;2012:370697. Central Venous Oxygen Saturation as a Predictor of Mortality Available from: https://dx.doi.org/10.1155/2012/370697. in Patients with Sepsis and Polytrauma in the Surgical Intensive 4. Balzer F, Sander M, Simon M, Spies C, Habicher M, Treskatsch Care Unit. Acad. Anesthesiol. Int. 2020;5(2):53-56. S. High central venous saturation after cardiac surgery DOI: dx.doi.org/10.21276/aan.2020.5.2.11 is associated with increased organ failure and long-term mortality: an observational cross-sectional study. Crit Care. Source of Support: Nil, Conflict of Interest: None declared. 2015;19(1):168. 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